With the news that Facebook is eyeing more than a $10 billion IPO, and twitter still growing strongly, it’s worth considering which company is the 3rd largest social network in the world.

It’s probably not a company you’ve heard very much about, and it’s not LinkedIn or MySpace. It is, in fact, Pinterest.

Experian, one of the world’s biggest online monitoring and reporting companies, has compiled their annual 2012 Digital Marketer: Benchmark and Trend Report. Whilst there’s a lot of great info in there, perhaps the chart getting the most attention is the almost ‘unknown’ rise of this seemingly niche Social network.

“Pinterest has jumped to the #3 social network position, ousting LinkedIn and falling only to Facebook and Twitter.
Pinterest’s traffic was up almost 50% from February to January 2012 and Pinterest’s unique visitors increased from 11 million to 17.8 million. One week during January yielded 21.5 million Pinterest visits, which is 30 times what its traffic was six months prior.
People are still most engaged on Facebook, spending an average of 405 minutes per month on it. They’re spending about 89 minutes per month on Pinterest.
But all you really need to know about Pinterest is in the chart below. Here’s what its total visits look like since last year — the past three months are nearly a vertical line.”

The question for Pinterest’s owners is how they’re going to make money. When the likes of Facebook are eyeing off $10 billion plus IPO’s and OMGPOP is acquired on the back of one addictive mobile game for $200 million, one has to wonder if Pinterest need do anything more than ad advertising to their service to become sufficiently valuable to potential suitors.